After a lengthy (and initially panicked) MSN conversation with Foggy, we (well, Foggy) deduced that my thermostat was broken as the temperature gauge is practically always on cold, no matter how far the car is driven. The only way to get it to move is when the engine is left idling for around 10 minutes. Apparently it's an easy, cheap and fast job, so I'm going to give it a shot this weekend.

What do I need to do the job? Cheers!

step 1 : start the car.
step 2 : rev the engine to a reasonable level, and hold it there for ~10 mins
step 3 : listen for the leccy fan.

if the fan comes on, the thermostat is fine, its just your temp gauge thats buggered.

IIRC, the fan didn't come on the other day when the car overheated..

Indeed its an easy job.


Remove Thermostat housing, clean up mating surfaces with fine sandpaper and then put new thermostat back in.

Tighten bolts up, but dont over tighten as alloy loves to crack when you tighten it up.

Hmm... I'm generally wrong when I try and explain something technical about engines (and that's even when talking about my own B172), but it sounds like there's a few things here all being called thermostats..

* There's the temperature sender in the engine block which is what controls the temerature gauge (Chapter 2, section 10 in my newer haynes manual). If this goes wrong then the gauge won't work.

* There's the Thermo-switch in the radiator, which once the water in the radiator gets to hot, the fan turns on (Book of Haynes Ch 2, section 11). If this goes wrong, your fan wont turn on.

* There is the thermostat which is a valve to control whether the water flows through the radiator circuit (if the water is cold, then it just flows through the engine, so it warms up faster). If this goes wrong, then not only will the fan not work, but the radiator and pipes in/out will be cold. (book of haynes, Ch 7). I've also seen just how much easier it is to change on a B14... (grumbles)

Hope this isn't wrong, and even better, hope it helps. It doesn't show I'm trying to avoid work, does it?

Oh, and as for actually fitting the temperature sender, all it really says is:-
* Unbolt the old one (cue gushings of water)
* Put new one on, with new sealing washer.
* Top-up/bleed cooling system

They don't even say where it is on the engine block... I could go have a look in the renault 5 outside with a B14, but it is rather dark and cold outside. Hopefully someone else will know.

HI, b14 thermostat is the easiest thermostat to change, cos it's in the top hose, look in front of the rocker cover and its the big hose going to the rad, you will see on the engine end it has two hose clips, one holds the hose to the engine, one holds the thermostat. undo both clips (thermostat one first) pull the hose off and remove dead stat. Fit new stat, replace hose and clips,top up and bleed coolant, job done, but looking at one of your other posts, have a good clean up on the terminals on the fan and the fan switch and check it works before driving it

do 340/60's have summer/winter thermostats like other cars ? if so maybe you just got a summer stat fitted so it opens quicker. also if you have time remove sender and put it in a pot of boiling water to see if the guage is working ok. you can do the same with the stat,take it out and drop it in a pot of boiling water to see if it opens,if it does take it out and then put it in a pot of cold water and see if closes.
its better to do this in case you damage the head or anything.